Automatically-operating scavenging valve for two-stroke cycle internal-combustion engines applicable also to compressors and the like



June 5, 1928. 1,672,436

E. O. P. THEGE AUTOMATICALLY OPERATING SCAVENGING VALVE FOR TWO-STROKECYCLE INTERNAL- COMBUSTION ENGINES APPLICABLE ALSO TO COMPRESSORS ANDTHE LIKE Filed June 24, 1926 bgzz mrenfor Patented June 5, 1928.

UNITED STATES 1,672,436 PATENT OFFICE.

EDVIN OSSIAN PARCIVAL THEGE, OF STOCKHOLM, SWEDEN, ASSIGNOR TO AKTIE-BOLAGET ATLAS DIESEL, OF STOCKHOLM, SWEDEN.

AUTOMATICALLY-OPERATING SCAVEI IGING VALVE FOR TWO-STROKE CYCLE INTER-HAL-COMBUSTION ENGINES APPLICABLE ALSO T0 COMPRESSORS AND THE LIKE.

Application filed June 24, 1926, Serial No. 118,303, and in Sweden July2, 1925.

For the removing of the combustion gases from the working cylinder oftwo-stroke cycle internal combustion engines scavenging valves have beenproposed comprising a springy valve plate. Such valves as these, afterthe piston has uncovered the openings of the working cylinder for theejection of the combustion gases from the cylinder and when the pressurein the said cylinder has been reduced to an amount below that of thescavenging air contained in the crank casing or a special receiver, areopened automatically by the scavenging air and are subsequently closedautomatically after the performance of the scavenging operation.scavenging valves of this construction are in many respects moresuitable than mechanically actuated scavenging valves. As is well known,the scavenging by means of fresh air ought to commence when the pressureof the combustion gases in the working cylinder is equal to orsomewhatlower than the pressure of the scavenging air. For that reasonan adjustment of the inechanically actuated scavenging valves must ,beefi'ected for the said purpose and it is not always certain that theproper adjustment is selected. In scavenging valves of the kind statedabove the opening of the. valve is efiected automatically at the momentstated and for that reason it is always sure that the valve operates insuch manner that an eflective scavenging is produced. hen automaticallyoperating valves are used the working cylinder, as is the case also whenmechanically actuated valves are provided, is charged, after theperformance of the scavenging operation, with fresh air under pressureand consequently contains a greater quantity of oxygen, for which reasona greater quantity of fuel may be admitted and burned thereby increasingthe horse power of the engine.

This invention relates to plate shaped elements by means of whichautomatically operating scavenging valves, applicable also tocompressors or the like, may be made up. The said elements are soconstructed that when put together a spacious passage for air isprovided, which is so located, that the air in the straightest possiblepath passes from the receiver or the like into the cylinder, in orderthat no reducing of the pressure of the scavenging air worth mentioningmay take place. The said object is gained by the plate shaped elementsbeing provided in their one surface with a row of parallel slot shapedopenings, which are located side by side and to which the air is led bycurved guides in the body of the element, and in their opposite sidewith a recess, which extends along the said row of openings and has acurved bottom, substantially parallel with the said guides. For theconstituting of a composed scavenging valve the said elements are placedon or at the side of each other in such manner, that the openings ofeach element are continued by the recess of the neighboring element. Aspringy valve plate is located between each two co-operating elements,which thus is common for the openings and for which when opened thecurved bottom of the recess constitutes a bearing surface, so that it isnot subjected to any abrupt bending operation which would result in thevalve plate being broken.

- A characteristic feature of the invention also consists in thescavenging valve, composed as stated above, being common to a pluralityof admission cylinder ports for the scavenging air and preferably beingso located that it is protected against the action of the hot combustiongases.

A scavenging valve composed of a 'plurality of plate shaped elements andspring valve plates in accordance with the invention is shown in theaccompanying drawing, in which Fig. 1 is a vertical section of the valveand the adjacent part of the working cylinder of the engine, the workingpiston being shown in side view, and

F ig. 2 is a horizontal section of the working cylinder and the receivercontaining the scavenging air; the figure shows in a lan view thescavenging valve and one 0 its elements. The valve is shown placed atthe side of one of the working cylinders of. inulticylinder engine.

1 is the working cylinder and 2 its piston. The admission ports for thescavenging air are designated by 3. The outlet opening (not shown) forthe combustion gases is arranged in the ordinary manner. 4 is thereceptacle or the receiver containing the scavenging air, whichreceiver, as usual, 15 common to the working cylinders. Scavenging airof suitable pressure is accumulated in the receiver either by a specialpump or by the working cylinders which then at their lower side of theworking pistons are adapted to compress the scavenging air. Anintermediate plate 6 provided with openings for the scavenging air isfixed to the cylinder by means of screws 5, the said plate serving as acarrier of the scavenging valve. The said valve consists of two sets ofplates 7. The plates of the one set are shown in a vertical section inFig. 1 and the uppermost late of the set is shown in a plan view in ig.2. The said plates are curve shaped and provided in one of its sides,according to the drawing the upper side, with transversal ribs orflanges 8, between which passages 9 for the scavenging air are provided.The top edges of the flanges 8 are flush with the wider end flanges 10of the plates, which flanges 10 extend downwards below the curve-shapedplate and to the level of the lowermost part of the plates 7respectively thus enclosing a transversal passage 11 extending along thewhole plate 7. The said plates are piled up as shown in Fig. 1. Betweenthe plates 7 plates 12 of a springy metal are jammed which act as valvesand are adapted in closed position to cover the channels 9.0f the plates7 respectively and in open position to connect the channels 9 with thechannels 11 respectively. Plates 7 and spring plates 12 are held betweena bottom plate 13 and a top plate 14, connected by means of screw bolts15 and nuts 16. In

the bottom plate 13 channels 9 are provided equal to the channels 9 ofthe plates 7. The shape of the lower side of the top plate 14 is equalto the shape of the lower side of the plates 7 and provided with achannel 11, which as the valve is open constitutes a continuation of thechannels 9 of the next subjacent plate 7. The set of plates thuscomposed, constituting one section of the scavenging valve, and thesection composed by a second set of plates of the same construction arejammed between the plate 6 and a plate 18 provided with openings 17,common to the valve sections respectively. The said plate 18 is fixed bymeans of screw bolts 19, connected with the receiver and provided withnuts 20. For the fixing of the position of the valve sectionsrespectively a set screw 21 is provided, screwed into the plate 13 andbearing against the bottom wall of the receiver. Th valve sections areput into the receiver and removed from the same through an opening inthe wall of the receiver provided with a cover 22.

The scavenging valve operates in the following manner. Piston 2 uncoversat the end of its working stroke the outlet port for the ccunlmstiongases and the ports 3 for the scavenging air in the usual manner. Assoon as the pressure in the working cylinder has been so reduced throughthe escaping of combustion gases, that it is lower than the pressure ofthe air contained in the receiver i, the said air opens the valve plates12 and passes through the channels 7, 11 and the ports 3 into thecylinder and ejects the remaining combustipn gases. Consequently, theopening of the scavenging valve is effected automatically at the propermoment. After the scavenging operation has been performed and thepressure in the working cylinder is substantially equal to the pressurein the receiver, the valve plates 12 will be closed by the elastic forceof the plates. The curve sha e of the lower side of the plates 7 is so aapted, that the springy late 12, while being opened, successively bearsagainst the said side, as shown in Fig. 1,

in which the springy plates 12 are shown in open position. Owing to thefact that a suitable curve shape has been imparted to the said bearingsurface for the springy plate 12, the said late will not be subjected toany abrupt ben ing dangerous for the durabilit of the same.

In the special form of execution of the scavenging valve shown in thedrawing and described above the channels 9 as well as the springy valveplates 12 are located in the natural or straight current direction fromthe receiver to the working cylinder. Owing to this fact a few or nopressure reducing whirls in the air current are created.

As perceived from the drawing, the scavenging valve is common toallports 3, which simplifies the construction. considerably. The distanceof the scavenging valve from the cylinder is so great, that the airremaining in the space between the valve and the cylinder after. eachscavenging operation protects the valve against the hot combustiongases.

The invention may, evidently, be modified in some respects, withoutexceeding the limits of the same.

I claim;

1. Plate shaped element for scavenging valves for two-stroke cycleinternal combustion engines and for valves for compressors and the like,provided in its one surface with a row of parallel slot shaped openings,which are located. side by side and to which the air is led by adiagonally extending guide in the. body of the element, and in itsopposite side with a recess extending along the said row of openings andhaving a curved bottom in order that, as a number of such elements areplaced on or at the side of each other, the openings of each element maybe continued by the recess of the neighboring element and a springyvalve plate may be common to the openings, for which valve plate whenopened the bot tfom of the recess constitutes a hearing surace.

2. Scavenging valve for two-stroke c cle internal combustion engines andfor va ves for compressors and the like comprisin a plurality of plateshaped elements, eac provided in its one surface with a row of parallelslot shaped openings, which are located side by side and to which theair is led by a diagonally extending guide in the body of the element,and in its opposite side with a recess extending along the said row ofopenings and having a curved bottom, said plates being so related toeach other that the openings of each element are continued by the recessof the neighbouring element, and a springy valve plate located betweenadjacent elements and common to the openings, for which valve plate whenopened the bottom of the recess constitutes a curve-shaped bearingsurface.

3. The combination of an admission valve as claimed in claim 2, thepassage for scavenging air of a two-stroke cycle internal combustionengine and a plurality of admis sion ports provided for the scaven ingair in the working cylinder of the engine, said valve being common tothe said ports.

4. The combination of an admission valve as claimed in claim 2, thepassage for scavenging air of a two-stroke cycle internal combustionengine, and a plurality of admission ports provided for the scavengingair in the working cylinder of the engine, said valve being common tothe said ports and located at such a distance-from the same, that an airuantit is confined between the valve and the 'sai ports sufiicient toprotect the valve against the action of the hot gases of combustion.

In testimony whereof I have hereunto afiixed my signature.

EDVIN OSSIAN PARoIvAL THEGE.

